body{
    background: snow;
}

#head{
    text-align: center;
    font-size: 20px;
    font-weight:bold;
    font-family:微软雅黑;
    margin-bottom: 15px;
}

#box{
    width:400px;
    height:200px;
    background: lightslategray;
    color:#b1e2fe;
    margin:0 auto;
    text-align:center;
}

#box .item{
    margin-top: 30px;
}

#box .number{
    width:50px;
    height:18px;
    vertical-align:middle;
}

#box #commit{
    vertical-align:middle;
}